My friend asked me if I received an email she sent me last week, so I told her I did get it, but forgot to reply. She then told me this: "I was just making sure that you had gotten my email [...]"
How is this correct? It seems a bit unnatural for her to use past perfect, when she could have said "I was just making sure that you received my email". She is American, so I assume it is correct, but I've never heard of such a phrase before.